An inexpensive, high-speed multiple-section, computed-tomographic X-ray transmission scanner has been designed. This scanner utilizes a novel multiple-anode, scanning-electron-beam-X-ray source to achieve scan speeds as low as 25 msec for a pair of adjacent-tomographic sections. No mechanical motion is involved. By scanning each of four anodes in sequence, 8 1.2 cm thick sections may be scanned in 100 msec. The system will have a dynamic capability enabling multiple-section scanning at a rate of 1/sec for 16 seconds (128 images). Alteratively, a single section may be scanned at a rate of 40/sec for .8 seconds (32 images). Two scanning speeds will be provided, a 25 msec mode primarily intended for motion studies, and a 50 msec mode intended for studies of myocardial perfusion and myocardial tissue damage. Faster scan speeds are feasible using a minor redesign of the system. A conventional stationary detector array using BGO-scintillation detectors will be used. Standard data processing techniques developed for conventional CT are planned. A commercial CT display and user interaction system, owned by UCSF, is available for viewing and data analysis, using sophisticated software developed in related projects. The technical performance, including image quality and system cost, are designed to be competitive with existing slow CT-body scanners. A comprehensive clinical evaluation is planned for the third year, following construction. Both animal studies and patient studies will be performed to evaluate the potential of this system for noninvasive cardiac imaging. Dynamic scanning of the entire heart (8-sections) in combination with intravenous contrast media injections will be used to quantitate blood flow in myocardial tissue, coronary arteries, and cardiac chambers, using indicator-dilution techniques established in a related program at UCSF. These methods will be used to evaluate the degree and extent of ischemic and infarcted myocardial tissue, directed toward the potential of the technique for performing a complete cardiac study.